Maybe I'm misreading your message, but you seem to be writing as if your counterpart in the discussion believes these things, despite saying nothing of the kind.
No I’m saying “censorship” as a rallying cry around moderation of a platform is effectively demanding permission for those. If you say a private company can’t moderate private messages it hosts, you’re saying it must allow private exchange of child porn. And harassing people with pictures of patterns of holes they find unnerving. And basically any harmful behavior you can imagine.
If Facebook wants to provide private messaging that’s actually so private they can’t know its content, that’s another story. But if they’re hosting messaging they know about, they’re entirely within their rights to decide what content is appropriate on their own resources.
>No I’m saying “censorship” as a rallying cry around moderation of a platform is effectively demanding permission for those.
I don't think so. The 2 specific situations you list are different. For child porn, it's illegal. So if Facebook blocks it, it's the government choosing what to censor, not Facebook.
And I think it's possible to prevent "harassing people with pictures of patterns of holes they find unnerving" without Facebook censoring content. Facebook has a block functionality, and the receiver could block the sender. As for the sender making multiple accounts, if Facebook blocks that, that's not censorship of content, that's enforcing a 1 account policy.
Am I misreading you?